Discovery and its tectonic significance of the ophiolite in the south of Xiemisitai Mountain, West Junggar, Xinjiang

Chagantaolegai ophiolite was discovered from the south of Xiemisitai Mountain, north to Heshituoluogai valley in West Junggar, Xinjiang. The ophiolite is represented by a ca. 18km long, north-northeast-striking serpentinite-matrix mélange, which encloses serpentinized peridotite, gabbro, basalt, spilite, chert blocks and homologous pyroclastic rocks. The LA-ICP-MS zircon U-Pb datings of gabbro in Chagantaolegai ophiolite are 517Ma±3Ma and 519Ma±3Ma, suggesting Early-Middle Cambrian. The REE patterns, trace element variation diagram and Nb/Yb-Th/Yb diagram show geochemical characteristics of Mid-ocean ridge ophiolite. Chagantaolegai ophiolite could be correlated well with Tarbagatai (Kujibai) ophiolite, Hongguleleng ophiolite in northern part of West Junggar and Zhaur ophiolite, Barkbek ophiolite in northern part of East Kazakhstan, thus providing more constraints for spatiotemporal characteristics of Chingiz-Tarbagatai Belt.